1. Field of the Invention
The invention is directed to an improved injection valve, in particular for an internal combustion engine of a motor vehicle.
2. Description of the Prior Art
One valve of the type with which this invention is covered is known in the industry and can be used in particular in conjunction with common rail injection systems for Diesel engines.
One known injection valve of this type includes a nozzle body, in which a nozzle needle is guided axially displaceably, and which has for instance six openings disposed at defined places, which lead to the combustion chamber of the internal combustion engine and are controlled by means of the nozzle needle. In the installed position of the injection valve, these openings are disposed such that a defined injection angle and a defined injection direction are assured.
The nozzle needle can be triggered by means of a valvelike actuating device, which is disposed in a so-called retaining body. By way of example, the actuating device can be equipped with a piezoelectric actuator unit, which serves to displace a so-called adjusting piston axially; via a hydraulic coupler, the adjusting piston cooperates with a so-called actuating piston, which in turn is connected to a valve closing member in such a way the pressure changes in a so-called valve control chamber can be brought about. The pressure changes in the control chamber lead to an axial displacement of the nozzle needle, as a result of which in turn the openings leading to the combustion chamber of the engine can be opened and closed.
The retaining body as a rule has wrench faces, which serve to fix and adjust the injection valve on a cylinder head of the engine. To enable establishing a defined injection angle, it must be assured that the retaining body and the nozzle body have a defined orientation to one another. Until now, this has been assured by means of centering pins disposed in bores of the retaining body or of the nozzle body.
However, such centering pins are difficult to install and can be sheared off when a nozzle lock nut connecting the retaining body and the nozzle body to one another is tightened.
Moreover, the centering pin bores reduce the high-pressure strength of the nozzle body, which can have an adverse effect especially in common rail injection valves, in which pressures of up to 1.4 kbar prevail. Bore tolerances, in the bores that receive the centering pins, also cause imprecise angular centering of the nozzle body and retaining body.